Insulation-displacement terminal fitting

Abstract

An insulation-displacement groove ( 24 ) is formed between blades (20) that project at right angles from opposed side walls ( 22 ). The insulation-displacement groove ( 24 ) includes a straight contact groove ( 26 ) directly below a guide groove ( 25 ). The guide groove ( 25 ) has an angled tapered shape defined by moderately sloped edges ( 31 ) at its upper side and steeply sloped edges ( 32 ) at its lower side. When a coated wire (W) is pushed in, cuts are made in a coating (Wb) by boundary portions ( 35 ) between the moderately sloped edges ( 31 ) and the steeply sloped edges ( 32 ). As the wire (W) is pushed further, a core (Wa) of the wire (W) is guided into the center of the contact groove ( 26 ) by the steeply sloped edges ( 32 ), consequently establishing a contact by being tightly held between contact edges ( 33 ).

What is claimed is:  
     
         1 . An insulation-displacement terminal fitting ( 10 ;  50 ), comprising an insulation-displacement groove ( 24 ;  41 ;  54 ) having at least one contact groove ( 26 ;  43 ;  58 ) for contact with a core (Wa) of an insulated wire (W) and at least one tapered guide groove ( 25 ;  42 ;  55 ) with a width that is gradually narrowed in an insertion direction (ID) of the coated wire (W) into the insulation-displacement groove ( 24 ;  41 ;  54 ), wherein the guide groove ( 25 ;  42 ;  55 ) has an angled tapered shape with a moderate inclination portion ( 31 ;  56 ) at a front side and a steep inclination portion ( 32 ;  57 ) at a back side with respect to the inserting direction (ID) of the coated wire (W) into the insulation-displacement groove ( 24 ;  41 ;  54 ).  
     
     
         2 . An insulation-displacement terminal fitting according to  claim 1 , wherein the contact groove ( 26 ;  43 ;  58 ) is adjacent the tapered guide groove ( 25 ;  42 ;  55 ).  
     
     
         3 . An insulation-displacement terminal fitting according to  claim 1 , wherein the insulation-displacement groove ( 24 ;  54 ) is formed between a pair of blades ( 21 ;  51 ) projecting from left and right side walls ( 22 ;  52 ) of the insulation-displacement terminal fitting ( 10 ;  50 ) to substantially face each other.  
     
     
         4 . An insulation-displacement terminal fitting according to  claim 1 , wherein the insulation-displacement groove ( 41 ) is formed in a portion of a bottom wall of the insulation-displacement terminal fitting bent substantially normal to the bottom wall.  
     
     
         5 . An insulation-displacement terminal fitting according to  claim 1 , wherein the insulation-displacement groove ( 54 ) is formed between a pair of blade portions ( 51 ) projecting inwardly substantially in V-shape when viewed in the insertion direction (ID) of the coated wire (W).  
     
     
         6 . An insulation-displacement terminal fitting according to  claim 1 , wherein cuts are made in a coating (Wb) of the coated wire (W) by boundary portions ( 35 ;  59 ) between the moderate inclination portions ( 31 ;  56 ) and the steep inclination portions ( 32 ;  57 ) of the guide groove ( 25 ;  42 ;  55 ), when the coated wire (W) is at least partly inserted into the insulation-displacement groove ( 24 ;  41 ;  54 ).  
     
     
         7 . An insulation-displacement terminal fitting according to  claim 1 , wherein a first angle (α) formed between the moderate inclination portion ( 31 ;  56 ) and a line normal to the wire insertion direction (ID) is at least about 45° and a second angle (β) formed between the steep inclination portion ( 32 ;  57 ) and the line normal to the wire insertion direction (ID) is between the first angle (α) and 90°.  
     
     
         8 . An insulation-displacement terminal fitting according to  claim 1 , wherein a spacing A between boundary portions ( 35 ;  59 ) between the moderate and steep inclination portions ( 31 ,  32 ;  56 ,  57 ) of the guide groove ( 25 ;  42 ;  55 ), a diameter B of a core (Wa) of the coated wire (W) and a width C of the insulation-displacement groove ( 24 ;  41 ;  54 ) satisfy a relationship A≧B≧C.  
     
     
         9 . An insulation-displacement terminal fitting according to  claim 1 , wherein a height of the moderate inclination portion ( 31 ;  56 ) along the insertion direction (ID) is at least half the height of the guide groove ( 25 ;  56 ).  
     
     
         10 . An insulation-displacement terminal fitting according to  claim 1 , wherein two insulation displacement grooves ( 41 ) are provided in longitudinally spaced positions, respective distal portions of blade portions ( 40 ) thereof being coupled by one or more coupling portions ( 45 ).  
     
     
         11 . An insulation-displacement terminal fitting according to  claim 1 , wherein the contact groove ( 26 ) and the tapered guide groove ( 25 ) are defined between a pair of blades ( 20 ) formed by making cuts in side walls ( 22 ) and bending the cut portions by substantially 90° with respect to the side walls ( 22 ).  
     
     
         12 . An insulation-displacement terminal fitting ( 10 ;  50 ) for use with a coated wire (W) having a core (Wa) with a diameter (B), comprising first and second opposed spaced-apart blades ( 21 ;  51 ) having opposed substantially parallel contact edges ( 33 ) spaced apart by a selected distance (C) less than the diameter (B) of the core (Wa) to define a contact groove ( 26 ;  43 ;  58 ), each said blade ( 21 ;  51 ) further having a steeply inclined edge ( 32 ;  57 ) adjacent the respective contact edge ( 33 ) and aligned at a first obtuse angle to the respective contact edge ( 33 ) and a moderately inclined edge ( 31 ;  56 ) adjacent the steeply inclined edge ( 32 ;  57 ) and aligned to the respective contact edge ( 33 ) at a second obtuse angle, the second obtuse angle being less than the first obtuse angle, each said steeply inclined edge ( 32 ;  57 ) meeting the moderately inclined edge ( 31 ;  57 ) at a boundary ( 35 ), the boundaries ( 35 ) of the respective blades ( 33 ) being spaced apart by a distance (A) that is greater than the diameter (B) of the core (Wa).  
     
     
         13 . The insulation-displacement terminal fitting ( 10 ;  50 ) of  claim 12 , further comprising first and second opposed side walls, the first and second blades ( 33 ) being unitary with the respective first and second side walls.  
     
     
         14 . The insulation-displacement terminal fitting ( 10 ;  50 ) of  claim 13 , wherein said blades ( 33 ) are substantially planar and lie in a common plane.  
     
     
         15 . The insulation-displacement terminal fitting ( 10 ;  50 ) of  claim 13 , wherein said blades ( 51 ) are substantially V-shaped.  
     
     
         16 . The insulation-displacement terminal fitting ( 10 ;  50 ) of  claim 12 , further comprising a bottom wall, the blades ( 40 ) extending unitarily and substantially normally from the bottom wall,  
     
     
         17 . An insulation-displacement terminal fitting ( 10 ;  50 ) unitarily formed from a metal material and comprising: a bottom wall, first and second opposed side walls extending from the bottom walls, first and second opposed spaced-apart blades ( 21 ;  51 ) aligned substantially normal to the bottom wall and between the side walls, said blades ( 21 ;  51 ) having opposed substantially parallel contact edges ( 33 ) spaced apart by a selected distance to define a contact groove ( 26 ;  43 ;  58 ), each said blade ( 21 ;  51 ) further having a steeply inclined edge ( 32 ;  57 ) adjacent the respective contact edge ( 33 ) and aligned at a first obtuse angle to the respective contact edge ( 33 ) and a moderately inclined edge ( 31 ;  56 ) adjacent the steeply inclined edge ( 32 ;  57 ) and aligned to the respective contact edge ( 33 ) at a second obtuse angle, the second obtuse angle being less than the first obtuse angle.  
     
     
         18 . The insulation-displacement terminal fitting ( 10 ;  50 ) of  claim 17 , wherein the first and second blades ( 21 ;  51 ) define a first pair of blades ( 21 ), and wherein the insulation-displacement terminal fitting ( 10 ;  50 ) further defines a second pair of blades ( 21 ) spaced from the first pair of blades ( 21 ).  
     
     
         19 . The insulation-displacement terminal fitting ( 10 ;  50 ) of  claim 18 , wherein the blades ( 21 ) in each said pair are substantially coplanar.  
     
     
         20 . The insulation-displacement terminal fitting ( 10 ;  50 ) of  claim 17 , wherein the first and second blades are unitary with the respective first and second side walls.